Ruling 2118 — Buying and Selling

If a person sells a commodity on credit to someone who does not know its price and the seller does not tell him the price, the transaction is invalid. However, if he sells the commodity for a higher price to someone who knows its immediate exchange transaction price – for example, he says, ‘The commodity I am selling to you on credit is £10 more than its immediate exchange transaction price’, and the buyer accepts, there is no problem.